Digital cameras (image sensing devices) have prevailed which can photograph an image by a simple operation, convert the photographed image into digital image data, save the digital image data in a memory, and supply the digital image data to various devices. Digital cameras and printers which can be applied to a direct printing system are also becoming popular. The direct printing system can print by directly transmitting digital image data from a digital camera to the printer in order to use an image photographed by the digital camera as a photograph.
In general, the direct printing function is executed in accordance with specifications set in advance for a camera and printer. In order to make a direct printing-compatible digital camera and printer which have been manufactured and distributed, cope with a new direct printing function, their functions must be updated, which is difficult or often impossible. Direct printing systems having different specifications are not compatible with each other. For example, direct printing by wireless connection and direct printing by USB connection have been defined individually and developed in different ways. As a result, many devices corresponding to only direct printing by USB connection have already been marketed. Under the circumstances, demands have arisen for a direct printing adaptor which can implement direct printing by converting and transmitting different direct printing functions, and connecting devices having different printing specifications.
A print conversion adaptor in a conventional PC environment is called a print server. The print server is designed to, when a printer exists, complement and expand the printer function and share the printer between a plurality of users.
FIG. 31 is a block diagram for explaining a print server system in a conventional PC environment.
The print server system is formed from print servers 2115 and 2116 for controlling printers 2117 and 2119 which can be shared between clients 2111, 2112, and 2113. In this arrangement, when the clients 2111 to 2113 print using the printer 2117, a print process proceeds in the following procedures.
A given client (e.g., 2111) transmits document data via a network 2110 in order to request the print server 2115 to print. The document data is made up of a print command string for describing the print contents of a text, figure, and image on each page of the document. The print command string is also called PDF (Page Description Language). Upon reception of the document data from the client 2111, the print server 2115 temporarily stores the document data in a file called a spool in the print server 2115. Then, the print server 2115 reads out the stored document data, transmits it to the printer 2117, and instructs the printer 2117 to print. The printer 2117 processes the document data and prints it on a paper sheet.
In this manner, the print servers 2115 and 2116 are designed to accurately transmit printer information, via the print servers 2115 and 2116, to the clients (2111 to 2113) which utilize the print servers. The printer information is exchanged by local connection between the printers 2117 and 2119 and the corresponding print servers 2115 and 2116.
Japanese Patent No. 03486553 discloses an example of an adaptor which acquires a print status from a printer and communicates it to a client.
Japanese Patent No. 03573466 discloses a print server for a network system that supports an error notification, re-printing, interrupt instruction, and the like.
Since the print server is designated after the specifications of a corresponding printer are defined, it can support a more advanced function. Japanese Patent Laid-Open No. 11-184649 discloses an example in which a high-end print server functions as an adaptor for a plurality of low-end printers.
Japanese Patent No. 03495845 discloses a print server which registers the functions of a plurality of printers and selects a printer suitable for a print job.
To the contrary, a direct printing adaptor is required to play a role greatly different from that of a print server in the conventional PC environment. More specifically, if a new direct printing protocol is designed to construct a direct printing adaptor, compatibility with many existing products which have already been marketed is not guaranteed. Thus, an existing direct printing protocol must be utilized without any change. Since a plurality of direct printing protocols are greatly different in functions such as transmission of printer information and the like, the printing information and the like may not be accurately transmitted to a digital camera. For example, in direct printing by wireless connection, pure file transfer protocols are often used. These file transfer protocols do not define any transmission of device information and print job information unique to the direct printing.
Even if the above problems are solved, a new problem arises. The new problem will be explained by exemplifying a case where the following method is adopted as a solution to the problem.
An image file is printed by transferring it from a cellular phone with a camera (abbreviate as “cellular phone”) that comprises a transmission/reception unit of an infrared ray defined by IrDA (Infrared Data Association). The adaptor uses its infrared transmission/reception unit to receive the image file, and issues to a printer a print job for printing the image file. If transfer of the image file from the cellular phone is normally completed, the adaptor sends a transfer completion response to the cellular phone with the camera.
At this time, for example, when the adaptor issues, to the printer, a print job after the data transfer completion response, the printer may not print immediately because it is busy during printing of data from a PC, or may not print owing to a trouble such as shortage of paper sheets. The user of the cellular phone cannot recognize these problems from the operation result (transfer completion) of the cellular phone.
When the printer is connected to a PC, the PC may issue a print request to the printer while the cellular phone transfers an image. In this case, if the priority of printing by the printer is higher for the PC, printing corresponding to the print request from the PC is preferentially executed. For example, if printing starts in response to a print request from the PC while the user sets an L-size photographic sheet in the printer and transfers image data in order to print an image photographed by the cellular phone on the L-size photographic sheet, a document from the PC is printed on the L-size photographic sheet.
Most low-end printers do not have a liquid crystal screen on their main bodies, and entrust the display function of the print status of direct printing to a connected digital camera. When such a low-end printer is connected to a cellular phone via an adaptor, it is very difficult to transfer the print status of the printer to the cellular phone via the adaptor, and display the print status on the display of the cellular phone. The low-end printer has a poor UI function, and various print settings such as the paper size in printing cannot be achieved by only the printer. When a printer and a cellular phone are connected via an adaptor, the printer may not be able to instruct the adaptor to make the above-described print settings while the cellular phone transfers image data.
When a means for transmitting an image data to a printer from a cellular phone or digital camera serving as an image data source uses a low-speed interface such as IrDA, the printer is occupied by the data supply source during transfer of image data via the interface, greatly decreasing the availability of the printer.
After printing starts on the basis of image data from an image data source, ink or print sheets of the printer may run short during printer or printing may not be completed due to any error. Even in this case, however, connection between the image data source and the printer normally ends upon the completion of transferring image data from the image data source. The printer cannot notify the image data source that printing is not completed. This problem is revealed when direct printing is executed not by connecting a printer serving as a server and an image data source serving as a client by common protocols, but by absorbing the difference between their protocols by an intervening adaptor.
A long time may be taken for printing depending on the printer, in addition to a long time taken to transfer image data from a client to the printer. When the client is a battery-driven mobile device, the remaining battery amount of the client may run short before the completion of printing, or in the worst case, printing may not be completed. If the battery is not exhausted until the remaining battery amount runs short, but a long time is taken for direct printing, a subsequent operation of the mobile device cannot be guaranteed, posing a problem.
If image data is transferred from a client to an adaptor, but the adaptor cannot receive data from a printer because, for example, the printer is connected to a PC and prints data from the PC, data transfer from the adaptor to the printer must wait for a long time. Also in this case, the client must wait without receiving any data transfer completion notification. The battery is disadvantageously wasted when the client is a battery-driven mobile device.
Conventionally, the user cannot designate which of the completion of printing by a printer and release of a cellular phone upon the completion of data transfer from the cellular phone is given priority. No process proper to the priority order by the user is performed.